Native of California; introduced to Kew in 1877 by Sir Joseph Hooker, who had collected it at Chico. In foliage it is similar to A. tomentosa, the leaves remaining downy until they fall, but not so markedly so. The flower, too, is less downy, larger, broader, and more inflated. A. macrophylla differs from both in its smooth flowers, with a large bract on the stalk.